Buggy code:
class SimplexTableau implements Serializable { private static final String NEGATIVE_VAR_COLUMN_LABEL = "x-" ; private static final long serialVersionUID = - 1369660067587938365L ; private final LinearObjectiveFunction f ; private final List < LinearConstraint > constraints ; private final boolean restrictToNonNegative ; private final List < String > columnLabels = new ArrayList < String > ( ) ; private transient RealMatrix tableau ; private final int numDecisionVariables ; private final int numSlackVariables ; private int numArtificialVariables ; private final double epsilon ; private final int maxUlps ; private final double cutOff ; SimplexTableau ( final LinearObjectiveFunction f , final Collection < LinearConstraint > constraints , final GoalType goalType , final boolean restrictToNonNegative , final double epsilon ) { } SimplexTableau ( final LinearObjectiveFunction f , final Collection < LinearConstraint > constraints , final GoalType goalType , final boolean restrictToNonNegative , final double epsilon , final int maxUlps ) { } SimplexTableau ( final LinearObjectiveFunction f , final Collection < LinearConstraint > constraints , final GoalType goalType , final boolean restrictToNonNegative , final double epsilon , final int maxUlps , final double cutOff ) { } protected void initializeColumnLabels ( ) { } protected RealMatrix createTableau ( final boolean maximize ) { } public List < LinearConstraint > normalizeConstraints ( Collection < LinearConstraint > originalConstraints ) { <START_BUG> List < LinearConstraint > normalized = new ArrayList < LinearConstraint > ( ) ; <END_BUG> for ( LinearConstraint constraint : originalConstraints ) { normalized . add ( normalize ( constraint ) ) ; } return normalized ; } private LinearConstraint normalize ( final LinearConstraint constraint ) { } protected final int getNumObjectiveFunctions ( ) { } private int getConstraintTypeCounts ( final Relationship relationship ) { } protected static double getInvertedCoefficientSum ( final RealVector coefficients ) { } protected Integer getBasicRow ( final int col ) { } protected void dropPhase1Objective ( ) { } private void copyArray ( final double [ ] src , final double [ ] dest ) { } boolean isOptimal ( ) { } protected PointValuePair getSolution ( ) { } protected void divideRow ( final int dividendRow , final double divisor ) { } protected void subtractRow ( final int minuendRow , final int subtrahendRow , final double multiple ) { } protected final int getWidth ( ) { } protected final int getHeight ( ) { } protected final double getEntry ( final int row , final int column ) { } protected final void setEntry ( final int row , final int column , final double value ) { } protected final int getSlackVariableOffset ( ) { } protected final int getArtificialVariableOffset ( ) { } protected final int getRhsOffset ( ) { } protected final int getNumDecisionVariables ( ) { } protected final int getOriginalNumDecisionVariables ( ) { } protected final int getNumSlackVariables ( ) { } protected final int getNumArtificialVariables ( ) { } protected final double [ ] [ ] getData ( ) { } @ Override public boolean equals ( Object other ) { } @ Override public int hashCode ( ) { } private void writeObject ( ObjectOutputStream oos ) throws IOException { } private void readObject ( ObjectInputStream ois ) throws IOException , ClassNotFoundException { } }

Fix:
List < LinearConstraint > normalized = new ArrayList < LinearConstraint > ( originalConstraints . size ( ) ) ;